Unless you're a copyright lawyer I'd avoid the "I'm a lawyer" credential in these discussions.
Oh boy, guess what? Even have an LL.M in IP.
the initial step being obvious fair use
There's really no such thing as an obvious fair use. It's always fact-intensive, always case-by-case. And there's always the risk of times changing. Format shifting comes to us from the RIAA v. Diamond case, and it's terrifying to think of how differently that gone had it been litigated just a few years later when the iTunes Music Store was open. I'll agree though that the use of pirated books for training was a bad idea, in that it does not help how a court will perceive the AI developers. Never a good idea to piss off a judge, and it's clear these guys were not thinking.
Still, there's no market for AI analysis of books as far as I know, and the use was transformative in nature given that no one appeared to be reading them, they were just grist for the mill. This is actually more favorable to fair use than Google Books, which is intended for some human to ultimately use to get to read snippets of text in search results. Imagine how strong Google's case would've been if they'd said that searching for a string of text points you to a book with no snippet or anything else to tell you what's inside. Maybe a page or chapter number, for all the good that does.
Once you get over the training hurdle though, it looks like pretty smooth sailing. The model is demonstrably lossy. It's too abstract to mesh with the concept of an abridgement or condensation. You might be able to get snippets here and there out of it, but I would imagine that given a few examples to dive deep into analyizing, OpenAI can show that they appear because they're built out of common chains of text from multiple works, or are overrepresented due to multiple copies of the work. (Kind of like how the image-generating AIs are said to like to make fake Getty Images watermarks because it saw so many of them in training data, so it must be important)
Personally, I like their chances. Either way, it'll be interesting to see.